.dh {
  border: 1px solid red;
  width: 300px;
  height: 300px;
  perspective: 200px;
  .dh_box {
    width: 100px;
    height: 100px;
    transition: all 0.5s;
    background-color: pink;
    &:hover {
      // transform: translateX(50px);
      // transform: rotateZ(50deg);
      transform: rotateX(20deg);
    }
  }
  
}
.pre {
  border: 1px solid red;
  width: 300px;
  height: 300px;
  transform-style: preserve-3d;
  transition: all 2s;
  position: relative;
  div {
    position: absolute;
    top: 0;
    left: 0;
  }
  .front {
    width: 100px;
    height: 100px;
    background: yellow;
    
  }
  .back {
    width: 100px;
    height: 100px;
    background: green;
    transform: translateZ(200px);
  }
  &:hover {
    transform: rotateY(90deg);
  }
}
.example {
  // border: 1px solid red;
  width: 100px;
  height: 100px;
  transform-style: preserve-3d;
  transition: all 3s;
  
  div {
    position: absolute;
    top: 0;
    left: 0;
    width: 200px;
    height: 100px;
    

  }
  .hz {
    background-color: green;
    transform: translateZ(50px);
  }
  .yy {
    background-color: orange;
    transform: rotateX(90deg) translateZ(50px);
    
    
  }
  &:hover {
    transform: rotateX(-90deg);
  }
}
@keyframes a1 {
  from {
    width: 200px;
  }
  to {
    width: 300px;
  }
}
@keyframes a2 {
  0% {
    width: 200px;
  }
  50% {
    width: 300px;
    height: 200px;
  }
  100% {
    width: 350px;
    height: 350px;
  }
}
.anima {
  width: 200px;
  height: 100px;
  background-color: pink;
  animation: a2 2s;
}